1. Field of the Invention
This invention is related to a generic mechanism for an application server to determine which key of a Generic Authentication Architecture (GAA) would enable easy integration of additional application servers by extending an existing standard for User Security Settings (USS).
2. Description of the Related Art
Initial authentication (i.e., bootstrapping) of Third Generation Project Partnership (3GPP) Generic Authentication Architecture (GAA) is based on AKA (Authentication and Key Agreement Protocol). Depending on a mobile terminal, such as a mobile phone, and a Universal Mobile Telecommunications System (UMTS) Integrated Circuit Card (UICC) or subscriber identity module inserted in the mobile terminal, the 3GPP Generic Authentication Architecture (GAA) can have the following keys: Ks_int_NAF, Ks_ext_NAF, and Ks_NAF. Today, the number of services using GAA is quite small and a definition as to which key to use for the particular smart card or subscriber identity module can be implemented directly into a server of the Network Application Function (NAF) that offers the service to the user. However, such implementation at the server is not very scalable or easy to administer in case of changes, such as new use cases and changes or updates to existing services, or a user getting a new smart card. The changes or updates to the NAF would require manual configuration, which is especially difficult, if the NAF resides not in the home network of the user or subscriber, but in a third party network.
The Ks_int_NAF key is used for securing Hypertext Transport Protocol (HTTPS) between the smart card or subscriber identity module and the application server NAF. The application would reside in the smart card or subscriber identity module and the mobile terminal would only act as a modem. This mechanism may be used as an alternative to present OTA SMS configuration messages to download new updates or other SAT applications.
The only use case for the Ks_int_NAF key defined today is in Multimedia Broadcast/Multicast Service (MBMS). In MBMS, the NAF is configured according to the definitions in TS33.246 3GPP specification, attached hereto as Appendix A, the contents of which are hereby incorporated by reference. In MBMS, a choice as to which key to use is defined by the description of the specific keys in the specification TS33.246. Therefore for this use case, no key choice mechanism is required because the key is implemented directly into the NAF that is offering the MBMS service to the user.